变压器近距故障的原因与防误措施

Study on Causes of Transformer Short Distance Fault and Error Prevention Measures

阐述外部近距离故障,产生了大量直流分量,引起微机差动保护低压侧TA直流饱和,导致比率制定和二次谐波制动失效而造成变压器差动误动的典型案例。通过实验室模拟试验,揭示误动机理,提出现场通过微机差动保护TA变化处理,从而防御区域外近距离故障时引起差动误动作。

This paper expounds the typical cases of transformer differential maloperation caused by external short-range fault, resulting in a large number of DC components, causing TA DC saturation on the low-voltage side of microcomputer differential protection, resulting in ratio formulation and second harmonic braking failure. Through the laboratory simulation test, the misoperation mechanism is revealed. It is proposed to deal with the TA change of microcomputer differential protection on site, so as to prevent the differential misoperation caused by short-range fault outside the area.